Ferroelectric field-effect transistors integrated on 2D semiconducting platforms are extremely relevant for low power electronics. Here, we propose and demonstrate a novel phase-change ferroelectric field effect transistor (PCFE-FET) for steep switching applications. Our gate stack is engineered as a ferroelectric Lanthanum doped hafnium oxide (LHO) proximity coupled with Mott insulator TixO2x−1(Ny) and is integrated onto a 2D MoS2 channel. The interplay of partial polarization switching in the ferroelectric LHO layer and reversible field-tunable metal-insulator transition (MIT) in TixO2x−1(Ny) layer concomitantly triggers polar to non-polar phase transition in the LHO layer between 200 and 220 K. This results in distinctive step-like features in the channel current during DC measurements, and random current fluctuations in high-speed measurements with slim anticlockwise hysteresis. Our devices show subthreshold slopes as steep as 25 mV/dec at 210 K, breaking the Boltzmann limit. Our gate stack is also potentially tunable for operation at temperatures of interest, presenting innovative gate stack engineering approaches for low-power computing solutions.
@article{arxiv.2411.02054,
title = {Hafnia-based Phase-Change Ferroelectric Steep-Switching FETs on a 2-D MoS$_2$ platform},
author = {Sooraj Sanjay and Jalaja M. A and Navakanta Bhat and Pavan Nukala},
journal= {arXiv preprint arXiv:2411.02054},
year = {2024}
}